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Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: "B. Pym" <Nobody447095@here-nor-there.org> Newsgroups: comp.lang.lisp,comp.lang.scheme Subject: Re: A simple Lisp program -- algorithm and speed issues Date: Fri, 20 Sep 2024 06:44:24 -0000 (UTC) Organization: A noiseless patient Spider Lines: 73 Message-ID: <vcj5k6$vu13$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Injection-Date: Fri, 20 Sep 2024 08:44:24 +0200 (CEST) Injection-Info: dont-email.me; posting-host="a0826257f8080eff71f9956e8770cd16"; logging-data="1046563"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+9pi97Cqblx4jBWC4/4RJt" User-Agent: XanaNews/1.18.1.6 Cancel-Lock: sha1:26IZD4JyZxtIKuqJKis2eW8AUcg= Bytes: 2412 Hrvoje Niksic wrote: > Here is an interesting, not entirely academic problem that me and a > colleague are "wrestling" with. Say there is a file, containing > entries like this: > > foo 5 > bar 20 > baz 4 > foo 6 > foobar 23 > foobar 3 > ... > > There are a lot of lines in the file (~10000), but many of the words > repeat (there are ~500 unique words). We have endeavored to write a > program that would sum the occurences of each word, and display them I think he means: sum the numbers associated with the words. > sorted alphabetically, e.g.: > > bar 20 > baz 4 > foo 11 > foobar 26 > ... The file contains: foo 5 bar 20 baz 4 foo 6 foobar 23 foobar 3 bar 68 baz 33 Gauche Scheme (define (process file) (let1 result '() (with-input-from-file file (cut generator-for-each (lambda (item) (ainc! result (symbol->string item) (read))) read)) (sort result string<? car))) (process "output.dat") ===> (("bar" . 88) ("baz" . 37) ("foo" . 11) ("foobar" . 26)) Given: (define-syntax ainc! (syntax-rules () [(_ alist key val func default) (let ((pair (assoc key alist))) (if pair (set-cdr! pair (func val (cdr pair))) (set! alist (cons (cons key (func val default)) alist))))] [(_ alist key val func) (ainc! alist key val func 0)] [(_ alist key val) (ainc! alist key val +)] [(_ alist key) (ainc! alist key 1)]))